My Willys 3A and 3B Community
TECH FAQ SECTIONS => Engine compartment => Topic started by: 1955CJ-5 on December 02, 2020, 09:56:05 PM
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When I was rebuilding the CJ-3a I became obsessed with finding the correct, and functional, fuel pump. This resulted in several online purchases. I actually don't remember where the pump that is on my 3a came from, but it works and so I'm happy.
But I had this AC 4693 pump, which seemed pretty original except that it didn't work. It was so stiff you could not move the actuating arm. Turned out the upper/fuel diaphragm had turned to an inflexible solid.
Enter Then and Now Automotive.
https://www.then-now-auto.com/
I called and they had a kit....not cheap, but well.....it would keep me entertained for a while. For this pump, which is what I'm told is one of the last developments of the combination fuel/vacuum pump, I needed a FPA 207-A kit. The main difference being the vacuum diaphragm actuating arm which had two notches in the sides rather than a slot in the middle...easier to install....for some...
Here are a couple pictures. Not a step by step rebuild but I hope informative to others....
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Here are a couple pictures of the old valves verses the new.
I used a dremel stone to remove the staked portion that held the valves secure, then pried them out, on advice from Then and Now, with a screwdriver. Not pretty or delicate but it worked.
The valves in the fuel side dropped right in and are retained with the clip and screws.
The valves that were pressed in were a very tight fit, so I polished the edges a bit with the dremel and they reluctantly seated. They were going nowhere but I staked them anyway...ground a punch to the approximate shape to duplicate the original stake marks.
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Just a couple more pictures.
I used my trusty Sears combination vacuum/pressure gauge and the pump makes 3 1/2 lbs of fuel pressure and about 5 psi vacuum on the vacuum side, when pumped by hand...should work OK, if ever needed, This is a spare after all....
In the last picture you will see that the 4693 has a follower on the actuating shaft. Another improvement I suppose...
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One of the problems I ran into was that the new valve would not install in the circled location, as it would hit the shelf below.
Fortunately, having removed six of the old valves, two or three were serviceable and so I picked what seemed the best for that location.
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Here is a picture of the new replacement valve vs the old original.
The replacement is about 1/16" taller, so it bottomed out in that one location.